Implement content-addressed resource storage for raster images (#4148)

* Implement content-addressed resource storage

* Implement OPFS resource storage

* Remove ResourceStorage::read

* Review

node-graph/graph-craft/src/application_io/resource.rs

@@ -0,0 +1,43 @@
+#[cfg(not(target_family = "wasm"))]
+pub mod mmap;
+#[cfg(target_family = "wasm")]
+pub mod opfs;
+
+use graphene_application_io::{LoadResource, Resource, ResourceFuture, ResourceHash, ResourceStorage};
+use std::collections::HashMap;
+use std::sync::{Arc, Mutex};
+
+#[derive(Debug, Default)]
+pub struct HashMapResourceStorage {
+	resources: Mutex<HashMap<ResourceHash, Resource>>,
+}
+
+impl HashMapResourceStorage {
+	pub fn new() -> Self {
+		Self::default()
+	}
+}
+
+impl LoadResource for HashMapResourceStorage {
+	fn load(&self, hash: ResourceHash) -> ResourceFuture {
+		let result = self.resources.lock().unwrap().get(&hash).cloned();
+		Box::pin(async move { result })
+	}
+}
+
+impl ResourceStorage for HashMapResourceStorage {
+	fn store(&mut self, data: &[u8]) -> ResourceHash {
+		let hash = ResourceHash::from(data);
+		self.resources.get_mut().unwrap().insert(hash, Resource::new(Arc::<[u8]>::from(data)));
+		hash
+	}
+
+	fn contains(&mut self, hash: &ResourceHash) -> bool {
+		self.resources.get_mut().unwrap().contains_key(hash)
+	}
+
+	fn garbage_collect(&mut self, used: &[ResourceHash]) {
+		let used_set: std::collections::HashSet<&ResourceHash> = used.iter().collect();
+		self.resources.get_mut().unwrap().retain(|hash, _| used_set.contains(hash));
+	}
+}